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    Re: Abbreviation of Nautical Mile
    From: Robert Eno
    Date: 2005 Jun 7, 23:35 -0400

    I had a quick perusal through successive issues of Bowditch, starting from
    1926 and working my way foward through time. It was not until I reached the
    1966 reprint of the 1962 edition, that I found an abbreviation listed on
    page 65, as follows: "mi., M".
    On page 986 of the same edition, under chart symbols, the abbreviation is
    given as: "M".
    The 1984, two-volume Bowditch provides the same abbreviation on page 63,
    volume 1. On page 1163 of the same publication under Appendix A:
    Abbreviations, it is listed as "NM" and "n. mi".
    Moving on to Dutton's (14th edition) Section A, page 3 (at the end of the
    textbook) provides several possibilities: "M" "Mi" "NMI" & "NM".
    The 12th edition of Dutton's indicates that it is simply "M".
    In the 1955 edition, Volume 1 of the Admiralty Manual of Navigation
    indicates that: "...Except on charts where the symbol M is now adopted, the
    unit is always denoted by a ', which is also the symbol for a minute of
    British Publication, AP 1234, Air Navigation (Air Ministry, 1944) gives it
    as "n.m."
    By the look of it, you can take your pick. I find it rather odd that such an
    important unit of measure would not have a clearly unique and
    universally-accepted symbol. It is a real mixed bag.
    I generally use "nm" or "NM", depending on my mood that day.
    ----- Original Message -----
    From: "John Kabel" 
    Sent: Tuesday, June 07, 2005 10:58 AM
    Subject: Abbreviation of Nautical Mile
    > An interesting question came up the other day as we were editing a course
    > on Electronic Charting.  What is the accepted abbreviation of "nautical
    > mile"?  We need a standard that can be applied across all Canadian Power
    > and Sail Squadron courses.
    > I did some searching and came up with the following, to start the
    > discussion:
    > - Bureau International des Poids et Mesures notes that there is no
    > accepted
    > symbol, though all agree on the distance measured (1852 metres)
    > - neither the Canadian Metric Practice Guide nor the CSA publication
    > International System of Units have an abbreviation in their tables
    > - Wikipedia (the online encyclopedia) suggests that "nm" is preferred,
    > especially in aeronautics
    > - Canadian Hydrographic Service uses "M" in its Abbreviations
    > - The NOAA Chart 1 (Abbreviations) lists all of "M", "Mi", "NM" and "N M"
    > for "nautical mile(s)"
    > - Nav Canada, the agency responsible for air traffic control in Canada,
    > uses "NM"
    > - Bowditch (1995) gives both "n.mi." and "NM" in Abbreviations and
    > Acronyms
    > So, what does the group think?  What is USPS usage?  What is Navy usage?
    > Please reply either to the list or to me privately.
    > Thanks.
    > John Kabel
    > London, Ontario
    > --
    > Outbound e-mail is scanned for viruses.
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